From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.lixom.net (lixom.net [66.141.50.11]) by ozlabs.org (Postfix) with ESMTP id E13C267D5E for ; Thu, 5 Oct 2006 14:42:15 +1000 (EST) Date: Wed, 4 Oct 2006 23:41:41 -0500 From: Olof Johansson To: paulus@samba.org Subject: [PATCH] powerpc: Enable DEEPNAP power savings mode on 970MP Message-ID: <20061004234141.749b13fb@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, Without this patch, on an idle system I get: cpu-power-0:21.638 cpu-power-1:27.102 cpu-power-2:29.343 cpu-power-3:25.784 Total: 103.8W With this patch: cpu-power-0:11.730 cpu-power-1:17.185 cpu-power-2:18.547 cpu-power-3:17.528 Total: 65.0W If I lower HZ to 100, I can get it as low as: cpu-power-0:10.938 cpu-power-1:16.021 cpu-power-2:17.245 cpu-power-3:16.145 Total: 60.2W Another (older) Quad G5 went from 54W to 39W at HZ=250. Coming back out of Deep Nap takes 40-70 cycles longer than coming back from just Nap (which already takes quite a while). I don't think it'll be a performance issue (interrupt latency on an idle system), but in case someone does measurements feel free to report them. Signed-off-by: Olof Johansson Index: linux-2.6/arch/powerpc/kernel/cpu_setup_ppc970.S =================================================================== --- linux-2.6.orig/arch/powerpc/kernel/cpu_setup_ppc970.S +++ linux-2.6/arch/powerpc/kernel/cpu_setup_ppc970.S @@ -83,6 +83,22 @@ _GLOBAL(__setup_cpu_ppc970) rldimi r0,r11,52,8 /* set NAP and DPM */ li r11,0 rldimi r0,r11,32,31 /* clear EN_ATTN */ + b load_hids /* Jump to shared code */ + + +_GLOBAL(__setup_cpu_ppc970MP) + /* Do nothing if not running in HV mode */ + mfmsr r0 + rldicl. r0,r0,4,63 + beqlr + + mfspr r0,SPRN_HID0 + li r11,0x15 /* clear DOZE and SLEEP */ + rldimi r0,r11,52,6 /* set DEEPNAP, NAP and DPM */ + li r11,0 + rldimi r0,r11,32,31 /* clear EN_ATTN */ + +load_hids: mtspr SPRN_HID0,r0 mfspr r0,SPRN_HID0 mfspr r0,SPRN_HID0 Index: linux-2.6/arch/powerpc/kernel/cputable.c =================================================================== --- linux-2.6.orig/arch/powerpc/kernel/cputable.c +++ linux-2.6/arch/powerpc/kernel/cputable.c @@ -41,6 +41,7 @@ extern void __setup_cpu_745x(unsigned lo #endif /* CONFIG_PPC32 */ #ifdef CONFIG_PPC64 extern void __setup_cpu_ppc970(unsigned long offset, struct cpu_spec* spec); +extern void __setup_cpu_ppc970MP(unsigned long offset, struct cpu_spec* spec); extern void __restore_cpu_ppc970(void); #endif /* CONFIG_PPC64 */ @@ -221,7 +222,7 @@ struct cpu_spec cpu_specs[] = { .icache_bsize = 128, .dcache_bsize = 128, .num_pmcs = 8, - .cpu_setup = __setup_cpu_ppc970, + .cpu_setup = __setup_cpu_ppc970MP, .cpu_restore = __restore_cpu_ppc970, .oprofile_cpu_type = "ppc64/970", .oprofile_type = PPC_OPROFILE_POWER4,